There are a lot of factors involved in evaluation feedlot cattle for sickness, such as depression, temperature, rumen fill and the rest of the clinical picture. Other factors can also enhance or hinder evaluation of cattle.
When it’s cold outside, Jessica Laurin, DVM, Animal Health Center of Marion County, Marion, Kan., recommends that producers wait until after 10 a.m. to evaluate and pull cattle.
“It can take some time for cattle to get up, move around, eat, ruminate and warm up,” she says. “So many cattle will look cold before they have had a chance to get to the bunk and it doesn’t give an accurate picture.”
When it’s very hot out like much of the country experienced this summer, cattle will heat up pretty quickly during the day. “On those days, cattle should be evaluated for sickness before 10 a.m.,” Laurin suggests.
The ambient temperature can also affect attitude and behavior. “When it's very hot outside, clinical signs of heat stress pretty much look like illness due to disease. When it is very cold at night, cattle, especially smaller cattle, can act like they feel pretty cold and stiff first thing in the morning. Until they have had a chance to move around and fill, they can also look very similar to a sick calf.”
Laurin says if conditions are very dry or dusty, cattle may still have some snotty discharge early morning. “Once they have been up, moved around, and cleared their nose, they can look much different.”
Watch bunk behavior
Evaluating bunk behavior can also give indications of sickness. Healthy, hungry cattle will get shoulder-to-shoulder with each other and don’t mind being close together. “Many cattle feel better as a part of a collective group,” Laurin says.
But those that might be in the disease process tend to hang back where it’s less-dense and they won’t get jostled around. “You may have cattle that are feeling off or early in the disease stage that want to linger around their counterparts but do not have the appetite or aggression at the bunk. Those cattle stand right at the butts of those eating at the bunk or hang in the back of the pen.”
But not all of the outliers are sick. Laurin says during the first few days of the feeding period a producer should take the time to find the very timid cattle and work to train them to the bunk. “If they can identify them early and get those calves acclimated to the bunk or adapt the bunk or pen (even put a lick tub at the back of the pen) they can prevent the timid cattle from becoming pulled in two to three days due to being tired, stressed out and becoming sick.”
Taking the time to look at a new pen during different time periods in the day will help pen riders understand the pen's feeding behavior. That means looking at them during the hour period that the feed truck first comes through, then again in three to four hours, and again in the late afternoon.
“I was called out one day when a new pen was exhibiting overheating,” Laurin says. “The cattle were all clustered together around a full water tank late in the afternoon when the outside temperature was over 100° F. They didn't understand how to appropriately act and by clustering made themselves even hotter. By training them to spread out, along with spraying water on them and running water on the ground, we were able to get the cattle to catch a breeze and cool down.”